This invention relates to a system for moistening the gummed closure flaps of envelopes, and more particularly to a moistening device and associated liquid reservoir assembly for use in machines which process envelopes such as postage meter mailing machines.
Postage meter mailing machines generally have associated therewith devices to apply moisture to the gummed flap of an envelope and seal the envelope as operations ancillary to the application of postage thereto. Several systems for moistening envelope flaps have been utilized. U.S. Pat. Nos. 2,167,252 and 2,167,257 disclose moistening blades are generally machined from bronze stock and are costly to fabricate within the tolerances required. Moreover, the liquid reservoirs associated with such devices require careful handling for priming the blades and to avoid spilling when removing the reservoirs from the machine for refilling.
Another system for moistening envelope flaps, disclosed in U.S. Pat. No. 3,811,407, utilizes a wick positioned in a moisture applying means extending into a water reservoir. The moisture applying means is positioned below the deck of an envelope processing machine. The main body of an envelope travels on the deck as the flap travels below the deck. A spring like member forces the flap of the envelope to pass between it and the wick into firm contact with the wick so that wiping action of the gummed region of the flap against the wick is produced. In such a system the wick is essentially stationary and transfer of moisture is accomplished through capillary action of the hydrophilic synthetic resilient open cell foam material forming the wick.
Postage metering operations have become both high speed and relatively trouble free. Consequently, an operation ancillary to postage metering, such as envelope flap moistening, must be similarly high speed and reliable. Thus, although the moistening systems heretofor utilized have functioned with varying degrees of success it is nevertheless desirable to provide moistening systems which are reliable and high speed, as the postage metering operation, while at the same time being economical to produce and to maintain substantially problem free.